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Page:Popular Science Monthly Volume 81.djvu/306

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300
THE POPULAR SCIENCE MONTHLY

statement, and is in complete agreement with the results of gastric examination of fasting animals reported by numerous experimenters. There is no secretion into the empty stomach during the first days of starvation. Furthermore, persons suffering from absence of hydrochloric acid (achylia gastrica) declare that they have normal feelings of hunger. Hydrochloric acid can not therefore be called upon to account for the sensation.

Hunger not Due to Turgescence of the Gastric Mucosa.—Another theory, which was first advanced by Beaumont, is that hunger arises from turgescence of the gastric glands.[1] The disappearance of the pangs as fasting continues has been accounted for by supposing that the gastric glands share in the general depletion of the body, and that thus the turgescence is relieved.[2] This turgescence theory has commended itself to several recent writers. Thus Luciani has accepted it, and by adding the idea that nerves distributed to the mucosa are specially sensitive to deprivation of food he accounts for the hunger pangs.[3] Also Valenti declared two years ago that the turgescence theory of Beaumont is the only one with a semblance of truth in it.[4] The experimental work reported by these two investigators, however, does not necessarily sustain the turgescence theory. Luciani severed the previously exposed vagi after cocainizing them, and Valenti merely cocainized the nerves; the fasting dogs, eager to eat a few minutes previous to this operation, now ran about as before, but when offered food, licked and smelled it, but did not take it. This total neglect of the food lasted varying periods up to two hours. The vagus nerves seem, indeed, to convey impulses which affect the procedure of eating, but there is no clear evidence that those impulses arise from distention of the gland cells. The turgescence theory, moreover, does not explain the effect of taking indigestible material into the stomach. According to Pawlow, and to others who have observed human beings, the chewing and swallowing of unappetizing stuff does not cause any secretion of gastric juice.[5] Yet such stuff when swallowed will cause the disappearance of hunger, and Nicolai found that the sensation could be abolished by simply introducing a stomach sound. It is highly improbable that the turgescence of the gastric glands can be reduced by either

  1. Beaumont, loc. cit., p. 55.
  2. A better explanation perhaps is afforded by Boldireff's discovery that at the end of two or three days the stomachs of fasting dogs begin to secrete gastric juice and continue the secretion indefinitely. (Boldireff, Archives biologiques de St. Petersburg, 1905, XI., p. 98.)
  3. Luciani, Archivio di fisiologia, 1906, III., p. 54. Tiedemann long ago suggested that gastric nerves become increasingly sensitive as fasting progresses. ("Physiologie des Menschen," Darmstadt, 1836, III., p. 22.)
  4. Valenti, Archives italiennes de biologie, 1910, LIII., p. 94.
  5. Pawlow, loc. cit., p. 70; Hornborg, Skandinavisches Archiv für Physiologie, 1904, XV., p. 248.